Research Of All Optical Decoder Based On Cross Gain Modulation In Semiconductor Optical Amplifiers

All optical logic device has a wide application range in all optical communication network. The development of all optical logic device has a far reaching influence on future optical packet switching, optical computing, and optical transmission and so on. Semiconductor optical amplifier(SOA), due to its good nonlinear and high integration, is very suitable for the realization of optical logic functions. A single logic unit has a limitation in signal processing. In order to improve the network's capacity of information, the complex all optical logic operation circuits, such as adder, subtracter, decoder and selector, need to be developed. As one of the very important devices, decoder can transform one digital into another, its output can be used to drive or control the rest of the system, and it can also drive the monitor to display the numbers and the symbols. A novel scheme for all optical decoder based on cross gain modulation(XGM)in SOAs is proposed. It has high efficiency and wide wavelength range. The logical operations only have relations with the input optical power, so it neither needs precise phase nor polarization control. In the paper, we have a theoretical study in all optical decoder based on XGM in SOAs. The main contents are as follows:(1)The research background and significance of all optical logic device are introduced. Several kinds of all optical logic gates based on the nonlinear effects in SOA and the domestic and abroad development are summarized.(2)Theoretical basis for SOA is researched. The propagation equation for the optical field and the rate equation for the carrier density in SOA are derived. The nonlinearities of SOA are discussed.(3)A novel scheme for all optical decoder based on XGM in SOAs is proposed and the principle is analyzed. The mathematical model used in the scheme is introduced.(4)The static and dynamic gain characteristics of SOA are analyzed. This all optical decoder based on XGM in SOAs is simulated by simulation software OptiSystem7.0. The influence of the input pump power, the probe optical power, injection current of SOA on the properties, such as output power, output extinction ratio, are analyzed.